Calender和GregorianCalendar

　　Calender的中文翻译是日历，虽然之前有许多种计时的方法，不过为了计时的统一，现在最为普及和通用的日历就是GregorianCalendar。Calendar在Java中是一个抽象类，GregorianCalendar是它的一个具体实现。

Calendar获取时间的常见方法

import java.util.Calendar;
public class Test
{
    public static void main(String[] args)
    {
        Calendar cal = Calendar.getInstance();
        int year = cal.get(Calendar.YEAR);
        //比当前月份少1
        int month = cal.get(Calendar.MONTH);
        //date表示日期，day表示天数，所以date与day_of_month相同
        int date = cal.get(Calendar.DATE);
        int dayOfMonth = cal.get(Calendar.DAY_OF_MONTH);
        //表示本周的第几天，从周日开始计算
        int dayOfWeek = cal.get(Calendar.DAY_OF_WEEK);
        int dayOfYear = cal.get(Calendar.DAY_OF_YEAR);
        //12小时制
        int hour = cal.get(Calendar.HOUR);
        //24小时制
        int hourOfDay = cal.get(Calendar.HOUR_OF_DAY);
        int minute = cal.get(Calendar.MINUTE);
        int second = cal.get(Calendar.SECOND);
        int millisecond = cal.get(Calendar.MILLISECOND);
        int maxDate = cal.getActualMaximum(Calendar.DATE);
        System.out.println("现在的年份为:" + year);
        System.out.println("现在的月份为:" + month);
        System.out.println("现在的号为:" + date);
        System.out.println("现在的号为:" + dayOfMonth);
        System.out.println("现在是星期:" + dayOfWeek);
        System.out.println("现在过了的天数为:" + dayOfYear);
        System.out.println("现在几点:" + hour);
        System.out.println("现在几点:" + hourOfDay);
        System.out.println("现在几分:" + minute);
        System.out.println("现在几秒:" + second);
        System.out.println("现在几毫秒:" + millisecond);
        System.out.println("本月最后一天是:" + maxDate);
    }
}